Experientia, 1979 May 15, 35(5), 578 - 9 Polyamines as activators of AMP nucleosidase from Azotobacter vinelandii; Yoshino M et al.; Polyamines at physiological concentrations activate AMP nucleosidase from Azotobacter vinelandii . Biological significance of the activation is discussed in relation to the control of adenylate energy charge and the purine nucleotide synthesis in prokaryotes. Mol Cell Biochem, 1979 May 6, 25(1), 43 - 6 Myo-inositol-1-phosphate synthase from streptomyces griseus (studies on the biosynthesis of cyclitols, XXXVIII); Pittner F et al.; It could be shown that Streptomyces griseus, the microorganism producing the antibiotic streptomycin and also mutant strains of this species that cannot synthesize streptomycin, possess myo-inositol-1-phosphate synthase (EC 5.5.1.4), the enzyme cyclizing D-glucose 6-phosphate . The enzyme isolated from that organism is extremely instable, its molecular weight is approximately 260,000, and it requires a divalent metal ion for its activity . This is the first instance that an enzyme of this specificity has been found in a prokaryotic organism. J Protozool, 1979 May, 26(2), 290 - 4 RNA synthesis in isolated nuclei of the dinoflagellate Crypthecodinium cohnii; Rizzo PJ; Atypical eukaryotic RNA polymerase activity was demonstrated in nuclei of Crypthecodinium cohnii, a eukaryote devoid of histones . Nuclei were isolated from growing cultures of this dinoflagellate and assayed for endogenous RNA polymerase (EC 2.7.7.6) activity . There was a biphasic response to Mg2+ with optima at approximately 0.01 and 0.02 M MgCl2, but in contrast to other eukaryotic RNA polymerases, this enzyme activity was inhibited by low MnCl2 concentrations . In the presence of 0.01 M MgCL2 the optimum (NH4)2SO4 concentration was 0.025 M, a concentration at which the nuclei were lysed . Incorporation of {3H}UMP into RNA was inhibited by actinomycin D and dependent on the presence of undergraded DNA, and the reaction product was sensitive to ribonuclease and KOH digestion . Omission of one or more ribonucleoside triphosphates greatly reduced the incorporation . Only a slight enhancement of RNA polymerase activity resulted from the addition of various amounts of native and denatured calf thymus DNA . Spermine caused a marked inhibition while spermidine had little effect on RNA synthesis in the nuclei . Under the optimum conditions described in the present paper the nuclei incorporated approximately 3 pmoles of {3H}UMP/microgram DNA at 25 C for 15 min, and approximately 80% of this activity was inhibited by the eukaryotic RNA polymerase II inhibitor, alpha-amanitin (20 micrograms/ml) . A unique situation therefore exists in C . cohnii nuclei, in which absence of histones (a prokaryotic trait) is combined with alpha-amanitin-sensitive RNA polymerase activity (a eukaryotic trait). Z Naturforsch {C}, 1979 May-Jun, 34C(5-6), 374 - 80 Cyanide insensitive iron superoxide dismutase in Euglena gracilis . Comparison of the reliabilities of different test systems for superoxide dismutases; Lengfelder E et al.; Two proteins (P1 and P2, with weights of 57,500 and 27,500 respectively) were isolated from Euglena gracilis . Both proteins show cyanide-insensitive superoxide dismutase activity in the "classical" superoxide dismutase assay, using xanthine-xanthine oxidase as O2.- generator . If O2.- is generated chemically (autoxidation of reduced anthraquinone), photochemically (illuminated riboflavine) or pulse radiolytically, only protein P1 but not P2 shows SOD activity . Protein P1 contains 1 g atom (determined: 0.82) iron (no Mn or Cu) per mole protein and may thus be defined as iron-superoxide dismutase . Protein P2, showing the spectral properties of a flavoprotein, exhibits the activities of ferredoxin-NADP-oxidoreductase and "diaphorase" . The cyanide-insensitive SOD-activity of this Diaphorase" in the xanthine oxidase-assay for superoxide dismutase makes this classical and commonly used test unreliable for assay cyanide insensitive SOD activities . The existence of the "prokaryote-type" of superoxide dismutase (Fe-SOD) in Euglena gracilis is exceptional for an eukaryotic, autotrophically grown organisms. Biochim Biophys Acta, 1979 Apr 25, 577(2), 400 - 9 Comparative study between prokaryotes and eukaryotes by chemical iodination of ribosomal proteins; Bernabeu C et al.; Escherichia coli and Saccharomyces cerevisiae ribosomal proteins were chemically iodinated with 125I by chloramine T under conditions in which the proteins were denatured . The labelled proteins were subsequently separated by two-dimensional gel electrophoresis with an excess of untreated ribosomal proteins from the same species . The iodination did not change the electrophoretic mobility of the proteins as shown by the pattern of spots in the stained gel slabs and their autoradiography . The 125I radioactivity incorporated in the proteins was estimated by cutting out the gel spots from the two-dimensional electrophoresis gel slabs . The highest content of 125I was found in the ribosomal proteins L2, L11, L13, L20/S12, S4 and S9 from E . coli, and L2/L3, L4/L6/S7, L5, L19/L20, L22/S17, L29/S27, L35/L37 and S14/S15 from S . cerevisiae . Comparisons between the electrophoretic patterns of E . coli and S . cerevisiae ribosomal proteins were carried out by coelectrophoresis of labelled and unlabelled proteins from both species . E . coli ribosomal proteins L5, L11, L20, S2, S3 and S15/S16 were found to overlap with L15, L11/L16, L36/L37, S3, S10 and S33 from S . cerevisiae, respectively . Similar coelectrophoresis of E . coli 125I-labelled proteins with unlabelled rat liver and wheat germ ribosomal proteins showed the former to overlap with proteins L1, L11, L14, L16, L19, L20 and the latter with L2, L5, L6, L15, L17 from E . coli. Proc R Soc Lond B Biol Sci, 1979 Apr 11, 204(1155), 267 - 86 Symbionticism revisited: a discussion of the evolutionary impact of intracellular symbioses; Taylor FJ; Wallin (1927) first published the notion that the fusion of bacteria with host cells was the principal source of genetic novelty for speciation . He suggested that mitochondria are transitional elements in this process . While the significance that he attributed to symbiosis now seem excessive, he was one of the first authors to be aware of the evolutionary potential of symbiotic events and his view of mitochondria may not seem strange to many cell biologist today . The most significant evolutionary development which has been attributed to intracellular symbiosis is the origin of eukaryotic cellular organization . The current status of the 'serial endosymbiosis hypothesis' is briefly review . The case for the symbiotic origin of the chloroplast, based principally on 16 S RNA oligonucleotide cataloguing, is very strong . Mitochondrial origins are more obscure but also appear to be symbiotic due to recent 18 S cataloguing from wheat embryos . The probablility of the multiple origin of some eukaryotic organelles is also examined, the processes in question being the acquisition of distinct stocks of chloroplasts from disparate photosynthetic prokaryotes and the secondary donation of organelles from degenerate eukaryotic endosymbionts to their hosts, with specific reference to the dinoflagellates Peridinium balticum, Kryptoperidinium foliaceum and the ciliate Mesodinium rubrum . It is concluded that the evolutionary potential of intracellular symbiosis ('cytobiosis': a term introduced in this paper) is great, with the best established influence being on the origin of eukaryotic chloroplasts . Together with the potential effects of viral vectors, symbiosis serves as a supplementary speciation mechanism capable of producing directed evolutionary changes . It is likely that these processes will explain some of the apparent anomalies in evolutionary rates and direction which are not readily explicable by the conventional synthetic theory of evolution. J Parasitol, 1979 Apr, 65(2), 201 - 16 Lipids of Leishmania promastigotes; Beach DH et al.; A chromatographic analysis of lipids of cultured promastigotes of Leishmania donovani, L . braziliensis, L . mexicana, L . tropica, L . enriettii, L . hertigi, L . adleri, and L . tarentolae showed that total lipids were 2--15% of dry wt, and neutral and polar lipids were 14--55% and 45--86% of total lipids . Major lipid classes were as follows: sterol ester, triacylglycerol, sterol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylcholine . Predominant fatty acids were 18:2 (n - 6) greater than 18:3 (n - 3) greater than 18:1 (n - 9) greater than 18:0 greater than 22:6 (n - 3) greater than 22:5 (n - 6) greater than 16:0 greater than 14:0 greater than 18:4 (n - 3) greater than 20:3 (n - 3) . Some remarkable distributions of fatty acids among the phospholipid fractions were observed, as follows: diphosphatidylglycerol 18--33% 22:6 (n - 3); phosphatidylinositol 31--68% 18:1 (n - 9); phosphatidylcholine 13--41% 18:3 (n - 3) . Alk-l-enyldiacyl glycerols, and alk-l-enylacyl and alkylacyl forms of phosphatidylethanolamine and of phosphatidylinositol were found, and their glyceryl ethers and fatty adehydes analyzed . Notable in the phosphatidylethanolamine of some leishmanias was a cyclopropane fatty acid (4--11%), identified as cis-9,10-methylene octadecanoic acid by chromatographic, and by mass and proton resonance spectrometric analyses . The comparative biochemistry of the cyclopropane fatty acid, characteristic of many prokaryotes, and of alpha-linolenic acid, characteristic of photosynthetic plants, are commented upon. Nucleic Acids Res, 1979 Apr, 6(4), 1269 - 86 The use of rifampicin to evaluate tRNA transcriptional organization in Escherichia coli; Ludi GA et al.; The antibiotic rifampicin, which in prokaryotes inhibits the initiation of RNA synthesis but not the completion of nascent strands, was used to explore tRNA gene transcriptional organization in Escherichia coli . Cultures were grown in {32P} orthophosphate to constant specific radioactivity and labeled with {3H} uridine in the presence of rifampicin . Numerous tRNA species then were isolated by polyacrylamide gel electrophoresis and their 3H/32P ratios determined; these ratios, following correction for the base compositions of the tRNAs, should reflect the distances of the corresponding tRNA genes from their promoters . Individual tRNA species were identified, where possible, by oligonucleotide fingerprint analysis . Observed isotopic ratios were correlated with promoter-gene distances, measured in nucleotides, using the nucleotide sequence of the 16S ribosomal RNA gene as a reference . The protocols developed should be applicable to most prokaryotes. Ann Intern Med, 1979 Apr, 90(4), 642 - 7 Ultrastructure of the Legionnaires' disease bacterium . A study using transmission electron microscopy; Chandler FW et al.; The Legionnaires' disease (LD) bacterium appeared ultrastructurally identical in human lung, egg yolk membrane, and artificial media, seen as a blunt or tapering rod measuring 0.3 to 0.9 micron in diameter and greater than or equal to 2.0 micron long . Greatly elongated forms were commonly found in cultures and yold sac membranes after 5 to 7 days of growth but were only rarely seen in human lung . The LD bacterium was clearly prokaryotic . Prominent features included electron-lucent nucleoids interspersed among areas of well-defined ribosomes; cleanly circumscribed cytoplasmic vacuoles or granular inclusions; and a double envelope enclosure, each portion consisting of a triple-layered "unit" membrane, approximately 75 A wide . Division always occurred as a pinching, nonseptate process typical of bacteria with a double, gram-negative type of envelope . No definite structure was seen in the periplasmic space that might represent the peptidoglycan layer . These features of the LD bacterium confirm earlier reports of the gram-negative staining reaction of organisms obtained from cultures and preliminary evidence of their gram-negative ultrastructure . We found no unique features that would aid in the ultrastructural differentiation of the LD bacterium from other small gram-negative bacilli. Ann Intern Med, 1979 Apr, 90(4), 502 - 5 Microbiology of Legionnaires' disease bacterium; Isenberg HD; Legionnaires' disease bacterium in tissue does not readily react with the Gram stain but can be seen by other stains and direct immunofluorescence . It is a slow-growing, aerobic, gram-negative rod that can be cultivated over a narrow temperature range on Mueller-Hinton agar supplemented either with complex biological mixtures or certain ferric salts and cysteine . The bacterium produces unique, branched-chain fatty acids, catalase, oxidase (weakly), and gelatinase and uses starch while ignoring other carbohydrates . Pigment production is related to tyrosine in the medium . In-vitro studies suggest susceptibility to all antibiotics except vancomycin, but a class 1 beta-lactamase has been demonstrated . Analysis of DNA confirmed the unrelatedness of this bacterium to previously recognized prokaryotes . Diagnosis of the disease has depended largely on serologic test findings and the demonstration of the bacterium in tissue and, occasionally, on isolation . Additional, simpler, and more rapid diagnostic tests should soon be available. Arch Microbiol, 1979 Mar 12, 120(3), 297 - 9 Pulvomycin, an inhibitor of prokaryotic protein biosynthesis; Assmann D et al.; Antibiotic 1063-Z isolated from culture fluids of Streptoverticillium mobaraense was identified as pulvomycin . Pulvomycin was observed to inhibit protein biosynthesis in growing cells of Bacillus brevis . The poly(U)-directed poly(Phe) synthesis in cell-free systems of Bacillus brevis and Escherichia coli was highly susceptible to the antibiotic . Pulvomycin did not affect the transfer of Phe to tRNA . The results suggest that the target of pulvomycin action is the polypeptide chain elongation. Gene, 1979 Mar, 5(3), 197 - 206 Nomenclature of transposable elements in prokaryotes; Campbell A et al.; Transposable elements are defined as specific DNA segments that can repeatedly insert into a few or many sites in a genome . They are classified as simple IS elements, more complex Tn transposons and self-replicating episomes . Definitions and nomenclature rules for these three classes of prokaryotic transposable elements are specified. Gene, 1979 Mar, 5(3), 179 - 96 Summary and critique of the new NIH guidelines for recombinant DNA research; Szybalski W; New NIH Guidelines for research involving recombinant DNA (R-DNA) molecules were issued on December 15, 1978 . These are composed of four main parts, the first defining R-DNA and specifying prohibitions and exemptions, the second describing physical and biological containment, the third assigning the containment levels for many R-DNA experiments, and the fourth detailing the roles and responsibilities of the investigator, research institutions and NIH . Although the new Guidelines reduce restrictions, principally on those R-DNA experiments that use Escherichia coli K-12 host-vector systems, and exempt from the Guidelines several classes of experiments on prokaryotes that naturally exchange their DNA, most of their provisions are unjustified by the present assessment of the absence of any practical risks; many totally innocuous experiments are unnecessarily restricted and even virtually prohibited mainly because no host-vector systems were officially certified . The term Guidelines is a misnomer since they are mandatory regulations, even without any statutory basis . They impose large but unnecessary bureaucratic burdens on scientists, research institutions, research committees and NIH, and represent unwarranted censorship of basic research, which is antithetical to the creativity of human thought, thus posing serious dangers to the traditional freedom of inquiry. Biokhimiia, 1979 Mar, 44(3), 529 - 42 {Interaction of rat liver dexamethasone-receptor complexes with DNA}; Romanova NA et al.; Rat liver glucocorticoid-receptor complexes (GRC) acquire the ability to bind to DNA in a high affinity manner after activation by heating or precipitation with (NH)2SO4 . DNA is practically non-saturable by GRC in low salt buffers as well as in 0.15 M NaCl-containing buffer, although in the latter case the binding decreases approximately 3--5 times . GRC bind to homo- and heterologous prokaryotic DNA in a similar way; in both cases an addition of KCl (up to 0.15 M) to the medium is followed by the same decrease of the binding . This data suggest that the association of GRC with DNA observed in vitro is not accompanied by "recognition" of any certain DNA site . Besides DNA, activated GRC can associate with other polymers, charged positively (DEAE-cellulose) or negatively (RNA, polyvinylsulfate) . GRC interact very weakly with neutral compounds of the cellulose type but are strongly adsorbed on hydroxyapatite . Hence the activated GRC can be considered as an amphoteric protein . Salt solutions provoke dissociation of the GRC-DNA triple complexes: a complete dissociation is observed in the presence of 0,4 M NaCl or 0,4 M sodium phosphate buffer (pH 6,9) . Sodium phosphate buffer also elutes GRC from other sorbents such as DEAE-cellulose or hydroxyapatite . No significant dissociation of the GRC-DNA complexes is observed at sucrose concentration up to 2 M . The data obtained are indicative of an essential role of electrostatic forces for the interaction of GRC with DNA . The non-ionic detergent Triton X-100 at a concentration as low as 0,05% completely destroys the GRC-DNA triple complexes . The models explicating the selectivity of the genome activation by GRC without their "recognition" of any specific DNA sequences are proposed. Proc Natl Acad Sci U S A, 1979 Mar, 76(3), 1251 - 5 Membrane biogenesis: cotranslational integration of the bacteriophage f1 coat protein into an Escherichia coli membrane fraction; Chang CN et al.; The coat protein (CP) of bacteriophage f1 is integrated into an Escherichia coli plasma membrane fraction consisting of inverted vesicles when it is synthesized in a cell-free, coupled transcription--translation system supplemented with the inverted vesicles . By using proteolytic enzymes as probes, we found by subsequent peptide mapping and determination of the sequence of the proteolytic products that CP was inserted into the inverted vesicles in an orientation indistinguishable from that in inverted vesicles prepared from infected E . coli: only a COOH-terminal portion of approximately 10 residues was accessible to proteolysis, whereas the remainder of CP (CP') was entirely protected . Protection of CP' was dependent on the integrity of the vesicle membrane, because it was abolished when proteolysis was done in the presence of nonionic detergents . Insertion was observed when the inverted vesicles were present during translation in the cell-free system, not when they were added after translation . Thus, the asymmetric insertion of this type of integral membrane protein is strictly coupled to translation . These findings are discussed with respect to prokaryotic membrane biogenesis and are related to bacteriophage f1 assembly and infection. Proc Natl Acad Sci U S A, 1979 Feb, 76(2), 847 - 51 Molecular evolution of biomembranes: structural equivalents and phylogenetic precursors of sterols; Rohmer M et al.; Derivatives of one triterpene family, the hopane family, are widely distributed in prokaryotes; they may be localized in membranes, playing there the same role as sterols play in eukaryotes, as a result of their similar size, rigidity, and amphiphilic character . Their biosynthesis embodies many primitive features compared to that of sterols and could have evolved toward the latter once aerobic conditions had been established . Membrane reinforcement appears to be achieved in other prokaryotes by other mechanisms, involving either approximately 40-A-long rigid hydrocarbon chains terminated by one polar group acting like a peg through the double-layer or similar chains terminated by two polar groups acting like tie-bars across the membrane . These inserts can be tetraterpenes (e.g., carotenoids) . The biophysical function of membrane optimizers appears to have evolved toward sterols by changes limited to only a few enzymatic steps of the same fundamental biosynthetic processes. Proc Natl Acad Sci U S A, 1979 Feb, 76(2), 717 - 21 Interesting and unusual features in the sequence of Neurospora crassa mitochondrial tyrosine transfer RNA; Heckman JE et al.; The mitochondrial tyrosine tRNA from Neurospora crassa has been sequenced and found to have several interesting features: (i) It resembles prokaryotic rather than eukaryotic tyrosine tRNAs in that it possesses a large variable loop (loop III); moreover, it can be quantitatively aminoacylated by Escherichia coli tyrosyl-tRNA synthetase but not by yeast tyrosyl-tRNA synthetase . (ii) This tRNA differs from all tRNA's sequenced to date in lacking the A residue at position 14 and the constant purine residue at position 15, two nucleosides that have been found so far in loop I of all tRNA's and that have been implicated in base-base tertiary interactions, respectively, with the universal U residue at position 8 and the constant pyrimidine residue at the end of loop III . (iii) Unlike the N . crassa mitochondrial initiator tRNA, this tRNA contains the usual TpsiC sequence in loop IV and the highly conserved GG sequence in loop I common to other tRNAs. Hum Genet, 1979 Jan 25, 46(2), 209 - 17 Variability of bacterial gene-directed enzyme production in human genetically deficient cells; Horst J et al.; Human beta-galactosidase-deficient skin fibroblasts from a patient with generalized gangliosidosis (GMI-gangliosidosis type I) were treated with phage lambda plac DNA, coding for Escherichia coli beta-galactosidase (beta-D-galactoside galactohydrolase, EC.3.2.1.23) . New beta-galactosidase activity detected in cell extracts of phage DNA-treated GMI-gangliosidosis fibroblasts continued to vary considerably from one experiment to another . It behaved like the E . coli z-gene product upon immunochemical and physicochemical investigation . In some experiments the antigenic behavior of resultant beta-galactoside activity in lambda plac DNA-treated cells resembled that of mutant E . coli beta-galactosidase . Among the factors and variables that may be responsible for the variation in the results obtained here and elsewhere, low physical binding between prokaryotic mRNA sequences and fibroblast ribosomal RNA could play a part connected with effective translation . This hypothesis is discussed under the aspect of a comparison of the ribosomal binding site of lac z mRNA with the 3'-terminus of the eukaryotic 18s ribosomal RNA, which shows limited possibilities for base-pairing interactions . More extensive possibilities for forming Watson-Crick base pairs between their initiation site and the eukaryotic ribosomal binding site exist for other prokaryotic messengers, such as those of Q beta-replicase, f 1-coat protein, or UDPG-4-epimerase. Symp Soc Exp Biol, 1979, 33, 9 - 36 Translocation of proteins across membranes: the signal hypothesis and beyond; Blobel G et al.; Proteins are translocated across membranes either coupled to translation (co-translationally) or after translation (post-translationally) . The information for both modes of translocation is encoded in the protein in the form of a short-lived sequence extension (signal sequence) . Additional information resides in the ribosome in the case of co-translational translocation, which proceeds via a ribosome--membrane junction . Translocation is mediated by specific receptors (ribosome and/or signal receptors) which are restricted in their location to distinct cellular membranes . In most cases the signal sequence is removed by a signal peptidase operating in an endoproteolytic mode . Membranes endowed with receptors for co-translational translocation are: the rough endoplasmic reticulum (RER) including the outer nuclear envelope membrane, the inner mitochondrial membrane and the thylakoid membrane of chloroplasts, in eukaryotic cells; and the plasma membrane in prokaryotic cells . Each of these membranes presumably contains a single distinctive signal receptor, ribosome receptor and signal peptidase . Membranes endowed with one distinct receptor each for post-translational translocation are both mitochondrial membranes, the chloroplast envelope membrane and the peroxisomal membrane . A signal sequence for co-translational translocation across the RER membrane that is identical in its secondary structure is shared by secretory, lysosomal and certain bitopic integral membrane proteins . Some integral membrane proteins presumably share another common sequence--referred to as stop-transfer sequence--which serves to interrupt translocation and thereby to orient the polypeptide chain in the lipid bilayer . Furthermore, the existence of a few specific 'sorting' sequences is postulated . These would be common to many proteins and would serve to route them to their final destination following translocation across or orientation within the membrane . Thus, the topological information which determines the intracellular pathway and the final location of a great number of proteins appears to reside in a small repertoire of specific sequences which are either a transient or a permanent part of the protein. Biochimie, 1979, 61(2), 229 - 43 Effect of starvation on tRNA synthesis, amino acid pool, tRNA charging levels and aminoacyl-tRNA synthetase activities in the posterior silk gland of Bombyx mori L; Chavancy G et al.; Changes in the translational machinery components of the Bombyx mori posterior silk gland were analysed during starvation and refeeding and compared to the regularly fed larvae . During starvation, tRNA and ribosomal RNA synthesis are stopped . The amounts of different RNA classes and of the different tRNA species slow down at the same rate . Thus various tRNA show similar half-lifes and the preexisting tRNA adaptation to fibroin mRNA translation persists during starvation . Similarly, the tRNA/rRNA ratio is constant during starvation and refeeding (12 tRNA molecules for one ribosome) as in silk glands of control animals . Aminoacyl-tRNA synthetases and tRNA charging levels are decreased during starvation . The maximal tRNA charging level obtained during maximal protein synthesis in control animals is regained after 24 h refeeding of starved larvae . Changes observed in the free amino acid pool are not similar from one amino acid to another and levels reached after starvation do not differ strongly from the controls . Our results suggest that the production of translation apparatus components is coordinated and adjusted to the protein synthesis activity . Whether this coordination occurs in the silk gland is discussed on the basis of the "metabolic regulation", primarily described in prokaryotes and Yeast . Transfer RNA charging levels seem to play a key role in the process of regulation and could be implicated in the mechanism of tRNA adaptation if this phenomenon results as expected from a transcriptional control. Am J Clin Pathol, 1979 Jan, 71(1), 43 - 50 Ultrastructure of the agent of Legionnaires' disease in the human lung; Chandler FW et al.; This report confirms the gram-negative ultrastructural characteristics of the Legionnaires' disease organism by direct examination of pulmonary tissue from six confirmed cases--two from the original Philadelphia epidemic of 1976 and four from more recent sporadic cases . All microorganisms seen in all six lungs were identical ultrastructurally and were predominantely within intra-alveolar macrophages, as previously observed by light microscopy . They appeared as short, blunt rods that were clearly prokaryotic; i.e., they had diffuse electron-lucent nucleoid areas interspersed among areas of well-defined ribosomes, a pinching nonseptic division, and enclosure within a double envelope consisting of two three-layer "unit" membranes, each approximately 75 A wide . This structure, together with a pinching division, is typical of gram-negative bacteria . The Legionnaires' disease organism multiples both intracellularly and extracellularly in tissue and has no unique ultrastructural features that would aid in its specific identification . These findings are compared with recent reports describing the ultrastructure of what was considered to be the Legionnaires' disease organism in yolk sac and culture medium, and in one human lung. Scan Electron Microsc, 1979, (3), 549 - 64 Qualitative and quantitative aspects of labeling cell surface carbohydrates using lectins as probes; Lotan R; Lectins are proteins which bind mono- and oligosaccharides with great specificity . Many polysaccharides, glycoproteins and glycolipids which are important constituents of cell walls and surface membranes of prokaryotic and eukaryotic cells, contain sugar moieties with which lectins can interact . As a result lectins have been extensively used for the study of cell surface and membrane structure of their labeling . This paper reviews and evaluates the available methods for the preparation of fluorescent, electron-dense and radioactive lectin derivatives . The procedures involved in the visualization of lectin binding under light and electron microscopy are described . In addition, the methods for quantitative evaluation of the fluorescence on labeled cells and for analysis of the number of cell surface lectin binding sites using radioactively-labeled lectins are outlined . Examples are given for the application of fluorescent lectin derivatives for the detection of specific saccharide-containing molecules on the surfaces of living or fixed microbial cells and various normal and neoplastic cells . The use of lectins to demonstrate the dynamic nature of cell membranes and to detect changes in membrane structure or organization which occur or organization which occur during differentiation, development or after neoplastic transformation is discussed. J Supramol Struct, 1979, 10(4), 397 - 404 Structure of functional A salina -- E coli hybrid ribosome by electron microscopy; Boublik M et al.; Small 40S Artemia salina and large 50S Escherichia coli ribosomal subunits can be assembled into 73S hybrid monosomes active in model assays for protein synthesis . The reciprocal combination -- small 30S E coli and large 60S A salina -- fails to form hybrids . The 73S hybrid particles strongly resemble homologous 70S E coli and 80S A salina monosomes . The morphologic differences between the corresponding eukaryotic and prokaryotic ribosomal particles, established by electron microscopy, do not significantly affect the assembly and mutual orientation of 40S A slina and 50S E coli subunits in the heterologous monosome . The fact that the structure of the interface, the supposed site of protein synthesis, is preserved in the active hybrid implies that retention or loss of biologic activity of hybrid ribosomes is determined by the extent of conformational changes in the interface. Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 381 - 5 Evolutionary change in 5S RNA secondary structure and a phylogenic tree of 54 5S RNA species; Hori H et al.; Secondary structure models of 54 5S RNA species are constructed based on the comparative analyses of their primary structure . All 5S RNAs examined have essentially the same secondary structure . However, there are revealing characteristic differences between eukaryotic and prokaryotic types . The prokaryotic 5S RNAs may be further classified into two types, one having 120 nucleotides (120-N type) and another having 116 (116-N type) . A possible mechanism for the conversion of the prokaryotic 116-N type to the 120-N type 5S RNAs (or vice versa) is discussed on the basis of their nucleotide alignments . Finally, by comparing the nucleotide alignments, we propose a phylogenic tree of the 54 5S RNA species. Z Naturforsch {C}, 1979 Jan-Feb, 34(1-2), 33 - 7 Assimilatory nitrate reductase of Rhodopseudomonas capsulata AD2: a molybdo-hemeprotein; Alef K et al.; The assimilatory nitrate reductase of the phototrophic bacterium Rhodopseudomonas capsulata strain AD2 was purified to homogeneity by a combination of ammonium sulfate fractionation, chromatography on DEAE-cellulose and isoelectric focusing (isoelectric point of 4.8) . The purified enzyme was active only with reduced viologen dyes or reduced flavin as electron donors . Contrary to other bacterial assimilatory nitrate reductases, the enzyme was not inhibited by chlorate, but rather accepted this substance as an alternate substrate . The molecular weight of the enzyme was 185,000 dalton as determined by gelfiltration . Subunit analysis by sodium dodecyl sulfate (SDS) gel electrophoresis yielded a single protein band with a molecular weight of 85,000 dalton,, suggesting that the enzyme was composed of two identical subunits . The nitrate reductase contained 0.8 g-atoms molybdenum per 1.85 x 10(5) g protein and exhibited absorption maxima at 418, 523 and 552 nm in the reduced state (dithionite as reductant) . The nitrate reductase of Rps . capsulata AD2 is the first prokaryotic enzyme of the assimilatory type that has been shown to contain heme. J Supramol Struct, 1979, 12(3), 299 - 304 Gliding mycoplasmas are inhibited by cytochalasin B and contain a polymerizable protein fraction; Maniloff J et al.; Studies are presented on the effect of cytochalasin B (CB) on the growth of five Mycoplasma species, three Acholeplasma species, and one Spiroplasma species . The three gliding mycoplasma species (M gallisepticum, M pneumoniae and M pulmonis are the only mycoplasmas inhibited by CB . These are the only prokaryotes reported to be inhibited by CB . This suggested that these three mycoplasmas might have some sort of cytoskeletal structure . A protein fraction has been isolated from M gallisepticum which polymerizes in 0.6 M KCl and depolymerizes when KCl is removed . This fraction contains a major 58,000-dalton protein, a 46,000-dalton protein, and a minor 87,000-dalton protein. J Mol Evol, 1978 Dec 29, 12(2), 113 - 9 Bacteriophage MS2 RNA: a correlation between the stability of the codon: anticodon interaction and the choice of code words; Grosjean H et al.; The non-random distribution of degenerate code words in Bacteriophage MS2 RNA can be explained partially by considerations of the stability of the codon-anticodon complex in prokaryotic systems . Supporting this hypothesis we note that wobble codons are positively selected in codons having G and/or C in the first two positions . In contrast, wobble codons are statistically less likely in codons composed of A and U in the first two positions . Analyses of nucleotides adjacent to 5' and 3' ends of codons indicate a nonrandom distribution as well . It is thus likely that some elements of RNA evolution are independent of the structural needs of the RNA itself and of the translated protein product. Biochemistry, 1978 Dec 26, 17(26), 5804 - 10 Involvement of the mature domain in the in vitro maturation of Bacillus subtilis precursor 5S ribosomal RNA; Meyhack B et al.; A precursor of 5S ribosomal RNA from Bacillus subtilis (p5A rRNA, 179 nucleotides in length) is cleaved by RNase M5, a specific maturation endonuclease which releases the mature 5S rRNA (m5, 116 nucleotides) and precursor fragments derived from the 5' (21 nucleotides) and 3' (42 nucleotides) termini of p5A rRNA . Previous results (Meyhack, B., et al . (1978) Proc . Natl . Acad . Sci . U.S.A . 75, 3045) led to the conclusion that recognition elements in potential RNase M5 substrates mainly reside in the mature moiety of the precursor . Limited digestion of p5A rRNA with RNase T1 permitted the isolation of a number of test substrates which contained both precursor-specific segments and were unaltered in the immediate vicinity of the cleavage sites, but which differed in that more or less extensive regions of the mature moiety of the p5A rRNA were deleted . Tests of the capacity of these partial molecules to serve as substrates for RNase M5 indicate clearly that the enzyme recognizes the overall conformation of potential substrates, neglecting only the double-helical "prokaryotic loop" (Fox, G.E., & Woese, C.R . (1975) Nature (London) 256, 505). Science, 1978 Dec 22, 202(4374), 1257 - 60 Implications of RNA-RNA splicing in evolution of eukaryotic cells; Darnell JE Jr; The differences in the biochemistry of messenger RNA formation in eukaryotes compared to prokaryotes are so profound as to suggest that sequential prokaryotic to eukaryotic cell evolution seems unlikely . The recently discovered noncontiguous sequences in eukaryotic DNA that encode messenger RNA may reflect an ancient, rather than a new, distribution of information in DNA and that eukaryotes evolved independently of prokaryotes. Biochim Biophys Acta, 1978 Dec 21, 521(2), 459 - 69 Studies on the mode of action of hygromycin B, an inhibitor of translocation in eukaryotes; Gonzalez A et al.; Hygromycin B is an unusual aminoglycoside antibiotic active against both prokaryotic and eukaryotic cells . Hygromycin B at 0.38 mM concentration completely halts yeast cell growth in rich media, presumably by preventing protein synthesis by cytoplasmic ribosomes . Polypeptide synthesis in cell-free extracts from rabbit reticulocytes, wheat germ and yeast is strongly blocked by low concentrations of hygromycin B . The antibiotic inhibits peptide chain elongation by yeast polysomes by preventing elongation factor EF-2-dependent translocation, although it does not affect either the formation of the EF-2-GTP-ribosome complex or the EF-2- and ribosome-dependent GTP hydrolysis which takes place uncoupled from translocation . The inhibition of translocation by hygromycin B might result from the stabilization of peptidyl-tRNA bound to the ribosomal acceptor site, since the stability of {3H}Phe-tRNA-EF-1-poly(U)-ribosome and {3H}Phe-tRNA-poly(U)-ribosome complexes is increased in the presence of hygromycin B . The inhibition of polyphenylalanine synthesis by reticulocyte ribosomes and enzymic translocation of peptidyl-tRNA by yeast polysomes can be reversed by increasing concentrations of EF-2 suggesting a relationship between the binding sites of EF-2 and hygromycin B on the ribosome . Neither non-enzymic translocation, that takes place in the presence of high potassium concentrations, nor the peptide bondforming step are affected by hygromycin B. Mol Gen Genet, 1978 Nov 9, 166(3), 291 - 7 Eukaryotic ribosomal proteins stimulate Escherichia coli stringent factor to synthesize guanosine 5'-diphosphate, 3'-diphosphate (ppGpp) and guanosine 5'-triphosphate, 3'-diphosphate (ppGpp); Martini O et al.; When supplemented with Escherichia coli stringent factor, 80S ribosomes from various sources failed to support guanosine tetra- and pentaphosphate ((p)ppGpp) synthesis . In contrast, ribosomal proteins from 80S, 60S or 40S particles (mouse embryos, rabbit reticulocytes) crossreacted with the E . coli stringent factor . Significant stimulation of (p)ppGpp synthesis was achieved with a concentration as low as 5 micrograms of ribosomal proteins/ml . These observations may provide additional crtieria to detect homologies between eukaryotic and prokaryotic ribosomal proteins. Bull Soc Pathol Exot Filiales, 1978 Nov-Dec, 71(6), 412 - 6 {Presence of a prokaryote of the genus Haemobartonella Tyzzer and Weinman, 1939, in the blood of Nigerians in the Niamey region}; Gretillat S et al.; The hemograms of 97 bed-riddens in very bad conditions reveal the presence (74 more or less infected but 6 heavily) of cocci, rots, rings, commas, coloured by May-Grunwald and Giemsa stain against the cell membrane wall of the erythrocyts and sometimes free in the blood plasma . This procaryotic element is the same agent of the canine, feline, equine and cuniculine haemobartonellosis in Niger . Principal symptoms are general weariness, anaemia, arthralgies, dizziness, anguish, suffocation crisis . It is a disease of the deficient and underfed men in Sahel. Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5324 - 8 Pulvomycin, an inhibitor of protein biosynthesis preventing ternary complex formation between elongation factor Tu, GTP, and aminoacyl-tRNA; Wolf H et al.; Pulvomycin and the synonymous antibiotics labilomycin and 1063-Z are shown to inhibit prokaryotic protein synthesis by acting on elongation factor Tu (EF-Tu): in the presence of the antibiotic, the affinity of EF-Tu for guanine nucleotides is altered, the EF-Tu.GDP/GTP exchange is catalyzed, and the formation of the EF-Tu.GTP complex is stimulated . Hydrolysis of GTP by EF-Tu, induced by aminoacyl-tRNA, ribosomes, and mRNA or by kirromycin, is inhibited by pulvomycin . As shown by Millipore filtration, chromatographic analysis, and hydrolysis protection experiments, pulvomycin prevents interaction between aminoacyl-tRNA and EF-Tu.GTP to yield the ternary complex aminoacyl-tRNA.EF-Tu.GTP . Thus, enzymatic binding of aminoacyl-tRNA to ribosomes is blocked. Biochemistry, 1978 Oct 3, 17(20), 4260 - 5 Physical properties of Artemia salina ribosomes; Nieuwenhuysen P et al.; Eukaryotic ribosomes were isolated from the cryptobiotic embryos and from the further-developed free-swimming nauplii of the brine shrimp Artemia salina . Analytical boundary sedimentation and photon correlation spectroscopy yielded, respectively, the standard sedimentation and diffusion coefficients at infinite dilution, s degrees 20,w = 81 +/- 1 S and D degrees 20,w = (1.41 +/- 0.02) x 10(-7) cm2/s, for the unfixed and formaldehyde-fixed ribosomes from different developmental stages and for ribosomes attached to a messenger RNA fragment . Also, the density increment was determined, from which the partial specific volume was derived (0.63 +/- 0.01 cm3/g) . Combination of the different measured parameters gives accurate values for the molecular weight (3.8 +/- 0.1) x 106 and for size and solvation parameters . These results are compared with their counterparts for the smaller ribosomes from the prokaryote Escherichia coli. Lipids, 1978 Oct, 13(10), 686 - 91 Sterol-polyene antibiotic complexation: probe of membrane structure; Bittman R; Polyene antibiotics are useful tools for studying the role of sterols in biological membranes . The interaction of polyene antibiotics with membrane-bound sterols in artificial membrane systems, prokaryotic and eukaryotic cells, and lipid-containing viruses is reviewed . The pentaene macrolide, filipin, is shown to serve as a probe of phosphatidylcholine-sterol interaction and of the localization of cholesterol in the membrane of mycoplasmas. Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4901 - 5 Laser Raman evidence for new cloverleaf secondary structures for eukaryotic 5.8S RNA and prokaryotic 5S RNA; Luoma GA et al.; Neither of the two previously proposed secondary structures for eukaryotic 5.8S RNA is consistent with the present laser Raman results . A new, highly stable "cloverleaf" secondary structure not only fits the Raman data but also accounts for previously determined enzymatic partial cleavage patterns, base sequence and pairing homologies, and G-C and A-U base pair numbers and ratios . The new cloverleaf model also conserves several structural features (constant loops, bulges, and stems) consistent with known 5.8S RNA functions . Finally, we propose a similar new cloverleaf secondary structure for Escherichia coli 5S RNA, consonant with many known properties of prokaryotic 5S RNA. Nucleic Acids Res, 1978 Oct, 5(10), 3715 - 29 The turnover of tRNAs microinjected into animal cells; Schlegel RA et al.; Red cell-mediated microinjection has been used to study tRNA turnover in SV3T3 mouse cells and TC7 cells, an African green monkey kidney line . The turnover of endogenous tRNA, measured by labeling with 3H-methionine, was first-order with half-lives of approximately one day in SV3T3 and two days in TC7 cells . 32PtRNA isolated from E . coli or TC7 cells turned over at the same rate as endogenous tRNA when injected into either SV3T3 or TC7 cells . This demonstrates that cellular processes, not properties inherent to tRNAs, are responsible for the difference in tRNA turnover observed between SV3T3 and TC7 cells . These results further indicate that the mechanism of tRNA turnover in mammaliam cells does not distinguish prokaryotic from eukaryotic tRNAs . In contrast to unmodified tRNA, glyoxalated tRNA was rapidly degraded upon injection . Thus altered tRNA's, like altered proteins, are turned over more rapidly in animal cells. Biochim Biophys Acta, 1978 Sep 27, 520(2), 419 - 27 Neurospora crassa mitochondrial transfer RNAs; De Vries H et al.; Total mitochondrial tRNA from Neurospora crassa was characterized by base composition analysis, one- and two-dimensional gel electrophoreses and reversed-phase chromatography on RPC5 . The guanosine + cytidine content was about 43%, as compared to 60% for cytoplasmic tRNA . The modified nucleoside content was low and about the same as that of total yeast mitochondrial tRNA, though the G + C content is very different . We found psi, T, hU, t6A, m1G, M2G, m22G . Neither the eukaryotic "Y" base, nor the prokaryotic s4U were present . On two-dimensional polyacrylamide gel electropherograms about 25 species were separated . One species for phenylalanine, two for leucine and two for methionine could be located . Neurospora crassa mitochondrial tRNA does not hybridize with yeast mitochondrial DNA. Arch Microbiol, 1978 Sep 1, 118(3), 235 - 41 Isolation, characterization, and numerical taxonomy of Simonsiella strains from the oral cavities of cats, dogs, sheep, and humans; Kuhn DA et al.; Forty-nine strains of the gliding prokaryote Simonsiella were isolated from the oral cavities of cats (8), dogs (19), sheep (4), and humans (18) in Southern California by a direct isolation procedure using a complex serum-enriched medium . The numerical taxonomic analysis (unweighted pair-group method using arithmetric averages) of 57 differential traits for each strain was based on standard bacteriological diagnostic tests and included the molar guanine-plus-cytosine contents of the DNA and the relative percentages of fatty acid contents reported earlier . The resulting phenogram clustered the strains of Simonsiella into groups that correlated with sources of origin . The study included the neotype strain of Simonsiella crassa (ATCC 27504, ICPB 3651, NCTC 10283) of Australian sheep origin . The strains isolated from dogs, sheep, and humans form clusters of organisms that appear to have become adapted to live in and possibly to have evolved with their respective "hosts" . In our judgment, these source-of-origin clusters represent different "ecospecies". Biochemistry, 1978 Aug 22, 17(17), 3587 - 91 Rotational relaxation of 1,6-diphenylhexatriene in membrane lipids of cells acclimated to high and low growth temperatures; Martin CE et al.; Measurement of the time-resolved fluorescence depolarization of 1,6-diphenylhexatriene (DPH) in artificial bilayers of microsomal membrane lipids from Tetrahymena gives detailed information concerning the molecular motion of this probe and fluid properties of the membrane lipids which are obscured with steady-state methods . The rotational motion of DPH in these lipids from cells acclimated to 15 and 39.5 degrees C growth temperatures was anisotropic, which agrees with recent time-resolved studies of this probe in synthetic phospholipid systems . Evaluation of DPH polarization data obtained from these lipid fractions at their respective growth temperatures showed differences in physical properties which suggest that "viscosity", per se, of the microsomal lipids is not a strictly regulated as it is in prokaryotic systems . Rotational relaxation of DPH in 39.5 degrees C microsomal lipids measured at 15 degrees C is more complex than that of either lipid fraction measured at its actual growth temperature, suggesting that the probe has partitioned into two dissimilar environments within the bilayer . Similar effects are observed in the microsomes of 39.5 degrees C cells by freeze-fracture electron microscopy following rapid cooling to 15 degrees C . Under these conditions, two distinct regions are observed on the fracture faces, suggesting a correlation between lipid phase changes and alterations in membrane structure. Science, 1978 Aug 4, 201(4354), 444 - 5 Light-stimulated morphogenesis in the fruiting myxobacterium Stigmatella aurantiaca; Qualls GT et al.; When the fruiting myxobacterium Stigmatella aurantiaca, a gliding prokaryote, is starved on an agar surface, the cells form multicellular aggregates resulting from morphogenetic movements . In the presence of incandescent light, each aggregate develops into a structurally complex fruiting body, possessing a stalk and several sporangia . In contrast, this pattern of development is not seen when cultures are incubated in the dark . The cells form irregular interconnecting aggregates, which rarely develop into fruits . However, aggregates formed in the light will develop into fruits even if placed in the dark, suggesting that the light produced a relatively stable alteration in the phenotype of the cells. J Pediatr, 1978 Jul, 93(1), 106 - 9 Intracellular deoxyribonucleic acid--modifying activity of intermittent phototherapy; Santella RM et al.; Phototherapy is capable of damaging the genetic material of eukaryotic and prokaryotic cells at fluences considerably less than that received by irradiated infants . It has been suggested that intermittent phototherapy, with varying on-off cycles, may offer theoretical advantages since the total light dosage received by the exposed infant is reduced . The present study was undertaken to determine the effect of intermittent phototherapy on the genetic material of human cells in tissue culture . Intermittent illumination produced more DNA damage than a similar light dosage administered continuously . These results suggest that intermittent phototherapy regimens may prove more deleterious to irradiated infants than continuous phototherapy. Gene, 1978 Jul, 3(4), 315 - 31 Analysis of transposable elements inserted in the genomes of bacteriophages Mu and P1; De Bruijn FJ et al.; We have examined the genomes of the temperate bacteriophages Mu and P1 and some of their insertion mutants for hybridization with the prokaryotic transposable elements IS1 and IS2 . We used the DNA blotting-hybridization technique in which denatured DNA fragments are transferred to nitrocellulose paper directly from agarose gels and hybridized to 32P-labeled probe DNA . The 800 base pair insertion in an X mutant of Mu was found to hybridize with IS1 . The chloramphenicol resistance transposon, Tn9, in Mu X cam mutants was found to be located at or close to the sites of IS1 insertion in X mutants; Tn9 also hybridized with IS1 . The restriction endonuclease BalI cleaved IS1 once; it cleaved Tn9 in all Mu X cam mutants twice to release a fragment of about 1700 base pairs . These results support the conclusion that Tn9 contains one copy of IS1 at each end . In the P1cam isolate, from which Tn9 was transposed to Mu, BalI made a third cut in Tn9 giving rise to fragments of about 850 base pairs . The data further suggested that Tn9 is present in tandem copies in the P1cam isolate we examined . P1 itself was found to harbor IS1 . The two P1 strains tested had a common fragment containing IS1; one strain had an additional copy of IS1 . The IS1 element common to the P1 strains was shown to be the site of the Tn9 insertion in the P1cam isolate examined . No hybridization between IS2 and any of the Mu and P1 strains could be detected. Science, 1978 Jun 9, 200(4346), 1118 - 24 Microtubules in prokaryotes; Margulis L et al.; Longitudinally aligned microtubules, about 220 A in diameter, have been seen in the protoplasmic cylinders of the following spirochetes (symbiotic in the hindguts of dry-wood and subterranean termites): Pillotina sp., Diplocalyx sp., Hollandina sp . They are also present in a gliding bacterium from Pterotermes occidentis . These microtubules are probably composed of tubulin, as determined by staining with fluorescent antibodies to tubulin and comigration with authentic tubulin on acrylamide gels . Treponema reiteri lack tubulin by these same criteria . These observations support the hypothesis of the symbiotic origin of cilia and flagella from certain spirochetes. Nucleic Acids Res, 1978 Jun, 5(6), 2153 - 67 DNA-methylase from regenerating rat liver: purification and characterisation; Simon D et al.; DNA methylase has been purified 660-fold from nuclei from regenerating rat liver . The enzyme is able to methylate single stranded (ss) and double stranded (ds) DNA, the only reaction product being 5-methylcytosine . Previously unmethylated double stranded DNA from prokaryotes (M.luteus) as well as from eukaryotes (Ascaris suis) can serve as substrates . The synthetic copolymers (dG-dC)n . (dC-dG)n and (dG,dC)n are also methylated . While SV40 DNA is almost not methylated, PM2 DNA is a good substrate even in the supercoiled form . The enzyme methylates 1 in 17 bases in heterologous M.luteus DNA, but only 1 in 590 in homologous rat liver DNA . The high methylation level of M.luteus DNA, an analysis of the methylated pyrimidine isostichs and a preliminary dinucleotide analysis suggest that all the CpGs in a DNA can be methylated. Can J Biochem, 1978 Jun, 56(6), 440 - 3 The evolution of 5S RNA secondary structures; Sankofff D et al.; We have applied the Pipas-McMahon algorithm based on free energy calculations to the search for a 5S RNA base-pair structure common to all known sequences . We find that a 'Y' shaped model is consistently among the structures having the lowest free energy using 5S RNA sequences from either eukaryotic or prokaryotic sources . Compaison of this 'Y' structure with models which have recently been proposed show these models to be remarkably similar, and the minor differences are explicable based on the technique used to obtain the model . That prokaryotic and eukaryotic 5S RNA can adopt a similar secondary structure is strong support for its resistance to change during evolution. Biokhimiia, 1978 Jun, 43(6), 947 - 58 {Plant histones . Relevance to the evolution of prokaryotes to eukaryotes}; Gofshtein LV; There are many procaryotic and eucaryotic organisms in plant kingdom . It is hoped that the study of plant histones will be useful in evolutionary studies . The histones of great variety of animal species have been studied and well characterized . Less information is available concerning plant histones . The general conclusion drawn from these investigations is that most organisms of eucaryotic plant and animal species contain the same five major histone fractions . Recently the histone-like proteins were found in some primitive eucaryotes and procaryotes . Data on histones from higher and lower eucaryotes and histone-like proteins of procaryotes are reviewed . Evolution of histones and their appearance prior to that of eucaryotic cell is postulated . The role of histones in evolution of nucleosomes is discussed. Proc Natl Acad Sci U S A, 1978 Jun, 75(6), 2859 - 63 Conservation of ribosomal protein binding sites in prokaryotic 16S RNAs; Thurlow DL et al.; The Escherichia coli 30S ribosomal subunit proteins S4, S7, S8, S15, S17, and S20 that interact independently with 16S RNA from E . coli formed specific heterologous complexes with 16S RNAs extracted from 11 different prokaryotes covering a broad phylogenetic range . Complex formation was shown to be specific by saturation of binding in the presence of excess protein . Binding stoichiometries and the apparent affinities for a given protein varied depending on which 16S RNA was used, although the pattern of binding was not strictly correlated with phylogenetic relationships . The size-distribution of fragments resulting from limited hydrolysis of free prokaryotic 16S RNAs with T1 and pancreatic ribonucleases indicated that the structural organization of 16S RNA from E . coli is similar to that of 16S RNAs from closely related species, but differs, although to an unknown extent, from that of 16S RNAs from other prokaryotes tested . Digestions of RNA-protein complexes under similar conditions indicated that the proteins remain bound to specific RNA fragments . For those 16S RNAs isolated from species closely related to E . coli, the fragments were comparable to those generated by hydrolysis of the homologous complex. Proc Natl Acad Sci U S A, 1978 Jun, 75(6), 2829 - 33 Comparison of Artemia salina and Escherichia coli ribosome structure by electron microscopy; Boulik M et al.; The structure of eukaryotic Artemia salina and prokaryotic Escherichia coli ribosomes has been compared by electron microscopy . Despite the established differences in size and in the amount and proportion of the protein and RNA moieties, both types of ribosomes appear to have substantial similarity in the overall shape and in the mutual orientation of the subunits on the monosome . The small subunit is located in the "crown" region of the large subunit lengthwise between the two side crests . However, high-resolution electron microscopy reveals distinct differences in the fine structure of both small and large subunits . The 40S A . salina subunit with three structural domains is more complex than the corresponding E . coli subunit . The 60S A . salina subunit has a less expressed "crown" region and shows a knob-like protrusion in the base . Structural asymmetry is a characteristic feature common to subunits and monosomes from both A . salina and E . coli. Proc Natl Acad Sci U S A, 1978 May, 75(5), 2190 - 4 Homologous nucleotide sequences between prokaryotic and eukaryotic mRNAs: the 5'-end sequence of the mRNA of the lipoprotein of the Escherichia coli outer membrane; Pirtle RM et al.; The sequence of the first 89 nucleotides at the 5' end of the mRNA for the lipoprotein of the Escherichia coli outer membrane is: GCUACAUGGAGAUUAACUCAAUCU-AGAGGGUAUUAAUAAUGAAAGCUACUAAACUGGUACU-GGGCGCGGUAAUCCUGGGUUCUACUCUG . The sequence of the first 72 nucleotides was established by direct sequencing methods and was extended to 89 residues on the basis of the known sequences of oligonucleotides obtained from complete digestion of the mRNA by ribonuclease T1 or A and the known amino acid sequence of the prolipoprotein . The mRNA has an untranslated region of 38 residues before the initiation codon, AUG . A unique feature of the 5'-end sequence of the mRNA is that the sequence of 12 nucleotides (GUAUUAAUAAUG) prior to, and including, the initiation codon is the same as that found at the ribosome-binding site for 80S ribosomes in brome mosaic virus RNA4, a eukaryotic mRNA {Dasgupta, R., Shih, D., Saris, C . & Kaesberg, P . (1975) Nature 256, 624-628}. Biosystems, 1978 Apr, 10(1-2), 37 - 53 Modified bases in the DNAs of unicellular eukaryotes: an examination of distributions and possible roles, with emphasis on hydroxymethyluracil in dinoflagellates; Rae PM et al.; The occurrence of small amounts of one or more of several modified bases in the DNA of an organism is widespread in nature . Prominent among these bases are 5-methylcytosine, N6-methyladenine and 5-hydroxymethyluracil . All can be found in varying amounts in DNA of viral, prokaryotic and eukaryotic origin . In some organisms, modified nucleotides comprise a large fraction of DNA nucleotides and in others there is complete replacement of one of the common four nucleotides by a modified one . This article discusses the distributions and possible roles of the several modified bases found in prokaryote and eukaryote DNAs . Emphasis is given (1) methylcytosine in a broad variety of eukaryotes, (2) methyladenine in certain protozoa and protophyta and (3) hydroxymethyluracil in dinoflagellates . Attention is focused on the phenomenology and the possible consequences of the presence of hydroxymethyluracil in DNA. J Gen Microbiol, 1978 Apr, 105(2), 335 - 42 Dimethyl sulphoxide reduction by micro-organisms; Zinder SH et al.; Dimethyl sulphoxide (DMSO) was reduced to dimethyl sulphide by a wide variety of micro-organism, including prokaryotes and eukaryotes, aerobes and anaerobes . Dimethyl sulphone was not reduced by any of the organisms tested . Cell-free extracts of Escherichia coli reduced DMSO using reduced pyridine nucleotides as electron donors . Activity was greater in anaerobically grown cells than in those grown aerobically . Two other sulphoxides, methionine sulphoxide and tetramethylene sulphoxide, substantially inhibited DMSO reduction by extracts . Mutants of E . coli, which were unable to reduce biotin sulphoxide to biotin, were tested for their ability to reduce DMSO in whole cells and extracts . These mutants were in four different gene loci, bisA to bisD . DMSO reductase activity of the mutants was generally less than that of the wild-type strain, and activity depended upon the gene locus involved, the growth medium and the growth conditions . Only the bisA mutant had very low activity under all conditions . All of the bis mutants were able to grow using methionine sulphoxide as a sulphur source, indicating that biotin sulphoxide and methionine sulphoxide are reduced by different enzyme systems . DMSO may be reduced by both of these enzyme systems. Biochemistry, 1978 Mar 21, 17(6), 1015 - 27 Comparative kinetic studies of cytochromes c in reactions with mitochondrial cytochrome c oxidase and reductase; Errede B et al.; Kinetic studies of the reactions of selected eukaryotic and prokaryotic cytochromes c with mitochondrial cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase (EC 1.9.3.1) using a standardized complex IV preparation from beef heart are reported . Data on reactions with NADH-linked cytochrome c reductase (complexes I and III) are included . The concentration ranges employed provide a basis for quantitative demonstration of a general rate law applicable to oxidase reactions of cytochrome c of greatly differing reactivities . Results are interpreted on the basis of a modified Minnaert mechanism (Minnaert, K . (1961) Biochim . Biophys . Acta 50, 23), assuming productive complex formation between cytochrome c and free oxidase in addition to further complex binding of a second cytochrome c molecule to the initially formed oxidase complex . Kinetic constants so obtained are consistent with the assumption that binding is the dominant parameter in reactivity, and can be rationalized most simply on this basis. Biochem J, 1978 Mar 1, 169(3), 633 - 41 Purification and characterization of the class-II D-fructose 1,6-bisphosphate aldolase from Escherichia coli (Crookes' strain); Baldwin SA et al.; A new form of the class-II D-fructose 1,6-bisphosphate aldolase (EC 4.1.2.13) of Escherichia coli (Crookes' strain) was isolated from an extract of glycerol-grown bacteria . It has a higher molecular weight (approx . 80000)than previous preparations of the enzyme and closely resembles the typical class-II aldolase from yeast in size and amino acid composition . On the other hand, its kinetic behaviour is not typical of a class-II aldolase . The enzyme has no requirement for thiol compounds either for stability or activity, added K+ ions have no effect, and the optimum pH for the cleavage activity is unusually high . The class-II enzymes from the prokaryote E . coli and the eukaryote yeast show no immunological identity . However, the similarity of their structures suggests that they have evolved from a common ancestor. Biochem J, 1978 Mar 1, 169(3), 643 - 52 Novel kinetic and structural properties of the class-I D-fructose 1,6-bisphosphate aldolase from Escherichia coli (Crookes' strain); Baldwin SA et al.; Investigation of aldolase 1, the class-I D-fructose 1,6-bisphosphate aldolase (EC4.1.2.13) from Escherichia coli (Crookes' strain), showed it to have unusual kinetic and structural properties . The enzyme appeared to be larger than was previously supposed and may be a decamer with a mol . wt . of approx . 340000 . Its fructose 1,6-bisphosphate-cleavage activity was unaffected by these compounds . The enhancement exhibited a strong dependence on pH . These novel kinetic properties do not seem to be shared by any other fructose 1,6-bisphosphate aldolase, but recall the activation by polycarboxylic acids of the deoxyribose 3-phosphate aldolases from some other organisms . In view of its unusual properties, it is unlikely that aldolase 1 from E . coli is closely related to the class-1 aldolases that have been detected in several other prokaryotes, or to the typical class-1 enzymes from eukaryotes. Eur J Biochem, 1978 Mar, 84(1), 197 - 205 beta-Lapachone, an inhibitor of oncornavirus reverse transcriptase and eukaryotic DNA polymerase-alpha . Inhibitory effect, thiol dependence and specificity; Schuerch AR et al.; beta-Lapachone is a naturally occuring compound that can be isolated from a number of tropical trees . It is shown to be a potent inhibitor of reverse transcriptase activity from both avian myeloblastosis virus and Rauscher murine leukaemia virus . In addition, it affects eukaryotic DNA-dependent DNA polymerase-alpha activity: 50% inhibition is reached in 60-min incubation time by about 8 micron beta-lapachone . Enzyme activity is inhibited irrespective of the purity of the enzyme used or of the amount or type of template/primer or substrate present . The inhibitory effect of the drug is only observed in the presence of dithiothreitol . The primary site of action of beta-lapachone appears to be the enzyme protein, as is also borne out by the specificity of its action . Eukaryotic DNA-dependent DNA polymerase-beta, prokaryotic DNA-dependent DNA polymerase I, several other nucleic acid polymerases and some completely unrelated enzymes are not affected . Reverse transcriptase and DNA-dependent DNA polymerase-alpha may be in someway related in possessing similarly exposed '--SH structures' in their active sites . beta-lapachone thus affords a novel means of studying such interrelationships and of further characterizing enzymes. J Mol Evol, 1978 Feb 21, 10(4), 283 - 91 Ribosomal RNA homologies and the evolution of the filamentous blue-green bacteria; Bonen L et al.; Ribosomal RNA (rRNA) sequence homology (as determined by comparisons of T1 oligonucleotide catalogs of 32P-labeled 16S rRNAs) has been used to assess phylogenetic relationships within the filamentous and unicellular blue-green bacteria, and to identify regions of evolutionary conservatism within blue-green bacterial 16S rRNAs . Nostoc and Fishcherella, representatives of two morphologically distinct and highly differentiated orders, are shown to be as closely related (on the basis of RNA sequence homology) as typical members of the non-blue-green bacterial genus Bacillus . They are further shown to be (on the same basis) indistinguishable from typical unicellular members of a subgroup of the unicellular blue-green bacterial order Chroococcales . These results have general implications for studies of the origin of differentiated prokaryotes and of evolutionary change in prokaryotic macromolecules . In particular, they provide indirect evidence that the divergences of contemporary major prokaryotic groups are truly ancient ones. Biochem J, 1978 Feb 15, 170(2), 203 - 10 Studies on sex-organ development . Changes in chromatin structure during spermatogenesis in maturing rooster testis as demonstrated by the initiation pattern of ribonucleic acid synthesis in vitro; Mezquita C et al.; To probe the structural change in the genome of the differentiating germ cell of the maturing rooster testis, the chromatin from nuclei at various stages of differentiation were transcribed with prokaryotic RNA polymerase from Escherichia coli or with eukaryotic RNA polymerase II from wheat germ . The transcription was performed under conditions of blockage of RNA chain reinitiation in vitro with rifampicin or rifampicin AF/013 . With the E . coli enzyme, the changes in (1) the titration curve for the enzyme-chromatin interaction, (2) the number of initiation sites, (3) the rate of elongation of RNA chains, and (4) the kinetics of the formation of stable initiation complexes revealed the unmasking of DNA in elongated spermatids and the masking of DNA in spermatozoa . In both cases the stability of the DNA duplex in the initiation region for RNA synthesis greatly increased . In contrast with the E . coli enzyme, the wheat-germ RNA polymerase II was relatively inefficient at transcribing chromatin of elongated spermatids . Such behaviour can be predicted if unmasked double-stranded DNA is present in elongated spermatids. Microbios, 1978, 22(88), 103 - 33 Pillotinas and hollandinas: distribution and behaviour of large spirochaetes symbiotic in termites; To L et al.; Pillotina spirochaetes have been observed in the hindguts of wood-eating cockroaches (Cryptocercus punctulatus), and in 25 out of 28 species of termites examined . They were especially abundant in 21 species of dry wood termites of the family Kalotermitidae, from Europe, North America and Australia . These included many species of Kalotermes and one or a few of the following: Glyptotermes, Bifidotermes, Neotermes, Ceratokalotermes, Paraneotermes, Cryptotermes, Porotermes, Marginitermes, Pterotermes, Zootermopsis, Reticulitermes, Coptotermes, Heterotermes, and nasutitermitids . Identifications of pillotinas were made on the basis of large size (0.5--2 micromtere in diameter, 50 to greater than 100 micrometers in length) and wave pattern; these were verified by electron microscopy in K . schwarzi, Pterotermes occidentis and others . Pillotinas were also present in all species of subterranean termites (Family Rhinotermitidae) examined, and in the most primitive Australian termite, Mastotermes darwiniensis (Family Mastotermitidae) . They were not observed in damp wood termites (Family Hodotermidiae) . Pillotinas are invariably associated with a rich, complex xylophagous microbial community composed primarily of motile prokaryotes, and hypermastigote and polymastigote flagellates . Some have been previously described by those primarily concerned with termite hindgut protozoa . Observations were made on their modes of behaviour, division, and microbial associates . A new genus of spirochaetes, Hollandina, is also described . It is distinguished from Pillotina by a smaller size and several ultrastructural features, but is otherwise closely related taxonomically . Evidence is provided to support Hollande and Gharagozlou's (1967) concept that the pillotinas and hollandinas deserve the taxonomic status of 'family' and that they should be classified with the cristispire siprochaetes a-cording to the scheme developed by Hovind-Hougen (1976) . Spirochaetes are treated as a Phylum of the Kingdom Monera (Prokaryota) in the five kingdom system of Whittaker (1969). Acta Biochim Pol, 1978, 25(2), 129 - 46 Protein synthesizing system from wheat germ: efficient translation of synthetic and natural messages; Rychlik W et al.; Optimum conditions for translation of eukaryotic, prokaryotic and synthetic templates in wheat germ cell-free extract were determined . 1 . Translation of eukaryotic message (BMV RNA and TMV RNA) was at optimum at the same concentrations of K+, Mg(2+), HEPES and spermine . In optimal conditions the efficiency of translation was high, for BMV RNA being equal to 220 pmoles and for TMV RNA, to 280 pmoles of leucine incorporated per 1 microgram of template . Prokaryotic template (Qbeta RNA) was translated under different ionic conditions . 2 . Translation of synthetic template {poly(U)} was at optimum at fairly higher concentrations of K+ and Mg(2+) than those optimal for natural template translation . 3 . Efficient translation of natural and synthetic templates depends on complete removal of inhibitors found in the wheat germ cell-free extract . Action of these inhibitors could be mimicked by adenine nucleotides. Bull Cancer, 1978, 65(3), 283 - 97 Formation of thymine containing dimers in skin exposed to ultraviolet radiation; Johnson BE; Nuclear DNA appears to be the major molecular target for the inhibitory, mutagenic and lethal effects of ultraviolet radiation on cells in culture . Cyclobutyl dimers between adjacent pyrimidine bases, the major photochemical lesions for these effects in prokaryotes, also play a part in UVR effects on eukaryote cells . Pyrimidine dimers have been isolated from in vivo UV-irradiated guinea pig and mouse skin . The wavelength dependence for dimer induction is similar to that for acute skin reactions but no direct causal relationship has been established . Sunlight UVA may induce dimers in skin DNA . Excision of dimers from mouse skin in vivo is deficient as it is for most rodent cells in culture; human cell excision is efficient and the difficulties in interpretation of UV-carcinogenesis results with mice in terms of human skin cancer are therefore, increased. Arch Virol, 1978, 56(1-2), 15 - 31 Preparation of projection-less particles from influenza virus and their messenger activities in prokaryotic and eukaryotic systems; Arida EN et al.; A fraction of projection-less particles was prepared from influenza A/Dunedin/4/73 and A/Victoria/3/75 (X-47) (H3N2) by detergent treatment and extraction into ether at 0 degrees C . The activity of this material in stimulating protein synthesis in vitro was studied and compared with that of isolated virion RNA using a) an RNA-dependent E . coli system, and b) a wheat germ system . In the bacterial system the purified RNA had the highest template activity, while in the eukaryotic system the disrupted particle preparation was by far the most active . Translation products were formed with immunological and electrophoretic properties similar to those of several influenza virion proteins . The experiments indicate that, when added in the form of disrupted projection-less particles, RNA from influenza A2 virus is utilized as a template by eukaryotic ribosomes. Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 361 - 5 Detection of prokaryotic signal peptidase in an Escherichia coli membrane fraction: endoproteolytic cleavage of nascent f1 pre-coat protein; Chang CN et al.; An inverted membrane vesicle fraction isolated from uninfected Escherichia coli and largely derived from the inner membrane has been shown to contain an endoproteolytic activity that cleaves nascent bacteriophage f1 pre-coat protein into two identifiable products . The electrophoretic mobility on sodium dodecyl sulfate/urea/polyacrylamide gels and the partial amino-terminal sequence of the larger fragment were indistinguishable from those of the mature phage coat protein . Partial amino-terminal sequence analysis showed that the smaller fragment corresponds to the amino-terminal "signal peptide" of f1 pre-coat protein . Cleavage occurred only if the membrane fraction was present during in vitro synthesis, and was not observed if it was added after completion of pre-coat protein synthesis . The cleavage reaction was strongly stimulated when the membrane fraction was present together with the nonionic detergent Nikkol . These results are consistent with and discussed in terms of the signal hyothesis. J Biol Chem, 1977 Dec 25, 252(24), 9032 - 42 Studies of low molecular weight RNA from cells infected with adenovirus 2 . I . The sequences at the 3' end of VA-RNA I; Celma ML et al.; VA-RNA I is a low molecular weight RNA produced in large amounts in cells infected with adenoviruses . The 3' terminus of this RNA may represent a transcription termination site . We have demonstrated that this RNA occurs in infected cells in several forms which differ in the number of uridylic acid residues at the 3' ends . The nucleotide sequence of a DNA fragment overlapping the 3' end of VA-RNA I has been determined . The DNA could encode up to 4 uridylic acid residues at the 3' end of the RNA . The DNA sequence shows some similarity to known transcription termination sequences in prokaryotic systems. J Biol Chem, 1977 Dec 25, 252(24), 9047 - 54 Studies of low molecular weight RNA from cells infected with adenovirus 2 . III . The sequence of the promoter for VA-RNA I; Pan J et al.; VA-RNA I is one of the very few RNA species produced in animal cells whose transcriptional initiation site is known precisely . We have analyzed the nucleotide sequence of the DNA preceding the 5' end of VA-RNA I and compared it with known prokaryotic promoters and presumptive eukaryotic promoters. Z Naturforsch {C}, 1977 Nov-Dec, 32(11-12), 954 - 6 Characterization of a soluble NADH-independent nitrate reductase from the photosynthetic bacterium Rhodopseudomonas capsulata; Alef K et al.; The assimilatory nitrate reductase was purified 60-fold from a newly isolated, nitrate assmilating strain of the photosynthetic bacterium Rhodopseudomonas capsulata . The enzyme had a molecular weight of about 180 000 dalton and was typically prokaryotic in that it was not active with reduced pyridine nucleotides but rather with reduced flavins. J Exp Med, 1977 Nov 1, 146(5), 1182 - 94 Type I Escherichia coli pili: characterization of binding to monkey kidney cells; Salit IE et al.; We have demonstrated binding of purified pili from a strain of Escherichia coli to Vero cell monolayers as a model of prokaryotic-eukaryotic cell adherence . Pili bound to the tissue culture in a rapid reaction that did not require enzymatic activation . Attachment occurred optimally at pH 4-5 and could be inhibited by analogues of D-mannose, anti-pili antibodies, or by preincubation of tissue cells with mannose-specific plant lectins . Binding remained after treatment of the monolayer with glycosidases, trypsin, or a protease mixture but was enhanced after neuraminidase treatment . These results indicate that bacterial binding can occur via pili which act like lectins and presumably bind to mannose-containing glycoproteins on mammalian cell surfaces. Nature, 1977 Oct 20, 269(5630), 655 - 61 Recent excitement in the DNA replication problem; Alberts B et al.; It is now possible to reproduce most of the reactions involved in DNA replication using prokaryotic enzymes in vitro . Such systems have revealed that DNA replication is a complex process depending on a relatively large number of proteins, and that nucleoside triphosphate hydrolysis energy is used at several discrete steps . Much of the complexity of DNA replication may arise from the need for extreme copying fidelity. Nucleic Acids Res, 1977 Oct, 4(10), 3655 - 63 Sequence of the 3'-terminal 21 nucleotides of yeast 17S ribosomal RNA; De Jonge P et al.; The sequence of the 3'-terminal 21 nucleotides of 17S ribosomal RNA from the yeast Saccharomyces carlsbergensis has been determined to be (Y)G-m62A-m62A-C-U-C-G-C-G-G-A-A-G-G-A-U-C-A-U-U-AOH . This sequence shows extensive homology with the 3'-terminal sequence of 16S rRNA from Escherichia coli including the presence of the two adjacent N6-,N6-dimethyladenosines observed in the small subunit rRNA of eukaryotes as well as of many prokaryotes. Proc Natl Acad Sci U S A, 1977 Oct, 74(10), 4401 - 5 Computer analysis of nucleic acid regulatory sequences; Korn LJ et al.; We describe a computer program designed to facilitate the analysis of nucleic acid sequences . The program can search several nucleic acid sequences for oligonucleotides common to all of them . It can examine a DNA or RNA sequence for two kinds of homologous regions--repetitions and dyad symmetries . The homologies need not be perfect: mismatches and "looping out" of nucleotides are allowed . The program also finds (A+T)- and (G+C)-rich regions, locates restriction enzyme recognition sites, determines the distribution of di- and trinucleotides, and performs various other functions . We include two representative applications of the program . All published prokaryotic transcription termination sequences (June 1977) were found to share the following features: (i) a string of at least five T residues, (ii) the sequence CGGGC or a close analog immediately preceding the T cluster, (iii) a region of strong dyad symmetry preceding the Ts and including the CGGGC sequence . A sequence of 221 nucleotides consisting of the Escherichia coli trp promoter, operator, and leader was found to contain two strong dyad symmetries . These homologies both occur at known regulatory sites; no comparable homologies occur in regions without regulatory significance. Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 4041 - 5 Extraction of an actin-like protein from the prokaryote Mycoplasma pneumoniae; Neimark HC; An actin-like protein has been identified in cell extracts from the prokaryote Mycoplasma pneumoniae . This protein bears a striking resemblance to actin from vertebrates: (i) the solubility of the protein during isolation is analogous to that of actin bound to myosin (soluble in high ionic strength salt solution and insoluble at low ionic strength), (ii) sodium dodecyl sulfate treatment of the partially purified M . pneumoniae extract produces a protein with an electrophoretic mobility very close to that of vertebrate actin in sodium dodecyl sulfate/polyacrylamide gels, (iii) treatment of preparations with ATP-Mg2+ allows separation of long curvilinear filaments, 5-6 nm wide, that closely resemble eukaryotic filamentous actin, and (iv) the prokaryotic filamentous actin binds vertebrate heavy meromyosin fragments to form hybrid compleexes with the characteristic shape of periodic repeating arrowheads, and no heavy meromyosin is bound in the presence of ATP. Biokhimiia, 1977 Aug, 42(8), 1347 - 60 {Mitochondrial ribosomes}; Odintsova MS et al.; Some present-day conceptions on the structure and physiochemical and functional properties of mitochondrial ribosomes of higher and lower eukaryotes are reviewed . Mitochondrial ribosomes are compared to the ribosomes of prokaryotic and eukaryotic types and plastid ribosomes; biogenesis and functions of mitochondrial ribosomes are also discussed. Orig Life, 1977 Aug, 8(2), 155 - 68 The colonial rock-forming microfossils of the Bohemian Upper Proterozoic (Czechoslovakia), 'Bohemipora Pragensis' n.g., n.sp; Pacltova B; Large amounts of well preserved microfossils have been reported from the cherts of the Upper Proterozoic of the Bohemian Massif (Middle Europe) . They resemble those described by Cayeux (1894) from the Upper Proterozoic (Brioverian) of Bretagne (France) . It is shown, unlike the views of Cayeux and his followers (Deflandre, 1955, and Graindor 1957), that the observed structures did not belong to individuals but to colonies of filamentous prokaryotic organisms, most probably blue-green algae (Cyanophyta) . These produced specific crystal-like mineral aggregation round each filament . Scanning microscope examination has revealed that the individual facets of these mineral crystals were perforated by the openings through which the thread-like bodies of these primitive organisms protruded . It is shown that these microorganisms were attached to the cells of other, bigger microorganisms and enveloped them . Some of these substrate organisms might have been eukaryotic algae . The thecae gradually accumulated around the cells of these carrier organisms and after death the colonies disintegrated to constitute the main component of the sediment . The microfossils described are just a major component of a complicated fossil assemblage comprising coccoid and filamentous blue-green algae and bacteria . There are indications that several eukaryotic species might also have been present. Can J Microbiol, 1977 Aug, 23(8), 1096 - 108 Fimbriation in gliding bacteria; MacRae TH et al.; Of twenty-two strains of gliding prokaryotes examined, all but three were found to possess polar fimbriae . Fimbriae were not observed on two gliders, while Chloroflexus aurantiacus bore abundant peritrichous fimbriae . In some gliding bacteria, fimbriae were associated with 'holes' surrounded by an electron-transparent collar bearing 12 spike-like projections. Nucleic Acids Res, 1977 Aug, 4(8), 2831 - 41 A comparison of transcriptional linkage of tRNA cistrons in yeast and E . coli by the ultraviolet light technique; Feldman H; The ultraviolet light mapping technique was employed to determine the lengths of tRNA cistrons in yeast . The applicability of the method was first tested in the E . coli system, in which the mapping positions for some tRNA cistrons and the ribosomal 5S RNA genes as well as the existence of multimeric transcription units for tRNAs are known . Rates of the synthesis of the tRNAs and small rRNAs after irradiation with various doses of UV light were determined by pulse labeling and quantitation of the RNA species after twodimensional gel electrophoreses . The small ribosomal RNAs served for internal calibration in the estimtion of the target sizes . Our results suggest that--in contrast to the prokaryotic system--in yeast the majority of the tRNA genes are not linked into transcriptional units. Nature, 1977 Jul 14, 268(5616), 109 - 15 Transposable genetic elements as agents of gene instability and chromosomal rearrangements; Nevers P et al.; Transposable genetic elements in prokaryotes and eukaryotes, when inserted at a given locus, can control expression of the locus and cause large scale rearrangements of adjacent DNA sequences . Striking similarities in genetic behaviour between the two groups of elements have led to the proposal of a molecular model of eukaryotic controlling elements, and to suggestions about the part such elements may play in evolution and differentiation. Tsitologiia, 1977 Jul, 19(7), 711 - 24 {Role of the membranes in the regulation of the activity of genetic structures of bacteria and mitochondria}; Kazakova TB; The literature on DNA interaction with both the prokaryotic cell membranes and the mitochondria of the Eukaryota is surveyed . Data are presented in favour of membrane localization of DNA and of the regulatory role of membranes in genome expression . A possible "conformational" mechanism of the control of gene activity by conformational changes of membranes related to cell metabolism is discussed . The problems of protein-nucleic recognition are concerned. Mikrobiologiia, 1977 Jul-Aug, 46(4), 676 - 82 {Membrane composition of Actinomyces hygroscopicus in the course of growth and development}; Efimova TP et al.; The membranes of actinomycetes do not differ from the membranes of other prokaryotes in the content of lipids, proteins, carbohydrates, and RNA, Lipids are represented mainly by phospholipids, particularly by phosphatidyl ethanolamine, cardiolipine, and phosphatidyl glycerol . The fatty acid composition of phospholipids does not change in the course of growth, and is represented by 80 per cent with branched fatty acids having 15-17 carbon atoms . Over 20 fractions are found in proteins isolated from the membranes of actinomycetes grown for 1-3 days and studied by means of electrophoresis in polyacrylamide gel, and only 7-8 fractions, in the membranes of actinomycetes cultivated during 5-7 days. Proc Natl Acad Sci U S A, 1977 Jul, 74(7), 2973 - 5 Genetic instability in Drosophila melanogaster: putative multiple insertion mutants at the singed bristle locus; Golubovsky MD et al.; A series of eleven independent mutants at the X chromosome singed bristle (sn) locus of Drosophila melanogaster is described . All mutants descend from flies caught in the wild and bred in the laboratory . On the basis of their inordinately high spontaneous mutation frequency, ten of the mutants are classified as putative insertion mutants . Reversions to wild type occur at frequencies of 10(-4)-10(-3) . Some reversions appear to be losses of the inserted element, others appear (by analogy with prokaryotes) to be changes in the orientation of the inserted elements . Consistent with the insertion hypothesis, some sn mutants generate what are interpreted to be deletions at the sn locus . In their mutational properties, the sn mutants are analogous to insertion sequence (IS) elements and bacteriophage Mu of Escherichia coli, but the precise nature of the insertion remains unknown. Naturwissenschaften, 1977 Jul, 64(7), 366 - 70 {Biosynthesis and structure of the yeast fatty acid synthetase complex}; Schweizer E; Genetic as well as biochemical data suggest that the yeast fatty-acid synthetase complex has an (AB)6 protein structure where A and B represent multifunctional polypeptide chains with molecular weights of 185000 and 180000 daltons, respectively . Subunit A contains at least 3 and subunit B4 of the 8 known biochemical functions of the multienzyme complex . It is concluded that this complex structure has evolved from the corresponding prokaryotic system of monofunctional enzymes due to a selective advantage regarding the biosynthesis and assembly of the complex components. Eur J Biochem, 1977 Jul 1, 77(1), 69 - 75 The involvement of a complex between formylmethionyl-tRNA and initiation factor IF-2 in prokaryotic initiation; van der Hofstad GA et al.; A complex between initiation factor IF-2 and fMet-tRNA can be formed under ionic conditions, which are optimal for initiation complex formation . The complex can be retained on cellulose nitrate filters after fixing with glutaraldehyde . The IF-2 - FMet-tRNA complex formation is not influenced by GTP and GDP . Other nucleoside di of triphosphates also have no effect . Evidence is presented that this complex acts as an intermediate in polypeptide chain initiation . The IF-2 - fMet-tRNA complex formation is not influenced by initiation factors IF-1 and IF-3 . The binary complex can be bound to the 30-S subunit in the absence of GTP, which indicates that there is no concomittant binding of the IF-2 - fMet-tRNA complex and the nucleotide moiety to the 30-S subunit . The binding of the binary complex is stimulated by GTP . The influence of some inhibitors of initiation on the IF-2 - fMet-tRNA complex formation has been tested . Aurin tricarboxylic acid appeared to be a strong inhibitor, whereas the sulfhydryl reagents N-ethylmaleimide and p-chloromercuribenzoate had no effect. Proc Natl Acad Sci U S A, 1977 Jul, 74(7), 2706 - 9 Escherichia coli 5S RNA binding proteins L18 and L25 interact with 5.8S RNA but not with 5S RNA from yeast ribosomes; Wrede P et al.; Reconstitution experiments showed that the two Escherichia coli 5S RNA binding proteins L18 and L25 form a specific complex with yeast 5.8S RNA and not with yeast 5S RNA . The yeast 5.8S RNA-E . coli protein complex was found to exhibit ATPase and GTPase activities that had previously been observed for the E . coli 5S RNA-protein complex . The tetranucleotide UpUpCpG, which is an analog of the tRNA fragment TpsipCpG, interacted strongly with 5S RNA-protein complexes from E . coli and Bacillus stearothermophilus and weakly with yeast 5.8S RNA . UpUpCpG did not bind to E . coli, B . stearothermophilus, or yeast 5S RNA or to the yeast 5.8S RNA-E . coli protein complex . It is suggested that 5.8S RNA evolved from prokaryotic 5S RNA and that the latter two RNAs are related and have similar functions in protein synthesis. J Biol Chem, 1977 Jun 10, 252(11), 3952 - 60 Precursors of ribosomal RNA in the cellular slime mold Dictyostelium discoideum . Isolation and characterization; Batts-Young B et al.; The pathway of ribosomal RNA biogenesis in Dictyostelium discoideum has been defined through identification, isolation, and characterization of the rapidly labeled nuclear RNAs which are intermediates in the process . Comparison of the methylation patterns, base compositions, two-dimensional oligonucleotide maps, and hybridization properties of these intermediate RNAs with those of mature rRNAs has established clearly the precursor-product sequence relationships supporting the following scheme for rRNA production and processing: (formula: see text) The relationship of the 37 S RNA of Dictyostelium to primary rRNA transcripts of prokaryotes and other eukaryotes is discussed. Biosystems, 1977 Jun, 9(1), 35 - 42 Symbiosis and the evolution of prokaryotes; King GA; It is postulated, with support from kinetic modelling, that a succession of symbioses was the major process of evolution during the early stages of life . The process became less effective with the passage of time, while evolution by the natural selection of variants became more effective . The postulate may contribute usefully to discussions on the evolution of biochemical complexity and the structure of cells. Chromosoma, 1977 Apr 20, 60(4), 297 - 344 The diminution of Heterochromatic chromosomal segments in Cyclops (Crustacea, Copepoda); Beermann S; The chromosomes of Cyclops divulsus, C . furcifer, and C . strenuus, like those of several other Copepods, undergo a striking diminution of chromatin early in embryogenesis . The process is restricted to the presumptive soma cells and occurs at the 5th cleavage in C . divulsus, at the 6th and 7th in C . furcifer, and at the 4th in C . strenus . The eliminated chromatin derives from the excision of heterochromatic chromosome segments (H-segments) . Their chromosomal location is different in the three investigated species: Whereas in C . divulsus and C . furcifer the H-segments form large blocks-exclusively terminal in the former and terminal as well as kinetochoric in the latter-the germ line heterochromatin in C . strenuus is scattered all along the chromosomes . Extensive polymorphism exists with respect to the length of the terminal H-segments in C . furcifer, and with respect to the overall content of heterochromatin in the chromosomes of C . strenuus . In a local race of C . strenuus an extreme form of dimorphism has been found which is sex limited: females as a fule are heterozygous for an entire set of large (heterochromatin-rich), and a second set of small chromosomes in their germ line . Males are homozygous for the large set . In the first three cleavage divisions the H-polymorphism is solely expressed through differences of chromosome length . Following diminution the differences between homologous have disappeared . Feulgen cytophotometry demonstrates that in the three species the 1C DNA value for the germ line, as measured in sperm, is about twice that measured in somatic mitoses (germ line/soma C-values in picograms of DNA: C . strenuus 2.2/0.9, C . furcifer 2.9/1.44, C . divulsus 3.1/1.8) . - The data imply that chromatin diminution is based on a mechanism which allows specific DNA segments, regardless of their location and size, to be cut out from the chromosomes without affecting the structural continuity of the remaining DNA . The mechanism may be analogous to that of prokaryotic DNA excision. Orig Life, 1977 Apr, 8(1), 39 - 53 Symbiosis and the origin of life; King GA; The paper uses chemical kinetic arguments and illustrations by computer modelling to discuss the origin and evolution of life . Complex self-reproducing chemical systems cannot arise spontaneously, whereas simple auto-catalytic systems can, especially in an irradiated aqueous medium . Self-reproducing chemical particles of any complexity, in an appropriate environment, have a self-regulating property which permits long-term survival . However, loss of materials from the environment can lead to continuing decay which is circumvented by physical union between different kinds of self-reproducing particles . The increasing complexity produced by such unions (symbioses) is irreversible so that the chemical system evolves . It is suggested that evolution by successive symbioses brought about the change from simple, spontaneously arising, auto-catalytic particles to complex prokaryotic cells. Biokhimiia, 1977 Apr, 42(4), 598 - 608 {Fractionation and purification of DNA methylases and specific endonucleases from cells of Escherichia coli SK}; Nikol'skaia II et al.; Fractionation and purification of DNA methylases and specific endonucleases from E . coli SK responsible for DNA specificity to host prokaryotic cells were studied . The most efficient purification was achieved by precipitation of proteins by 0.6 saturated ammonium sulfate with subsequent chromatography on KM-cellulose and concentration of fractions by dialysis against glycerol . Under these conditions the methylase activity produced 4 discrete fractions . Due to purification the specific activity of methylases increased 11--20-fold in various fractions . Methylase from the first (A) and fourth (BII) peaks catalyzed the methylation of cytosine to produce 5-methylcytosine; methylase from the third peak (BI) methylated adenine to produce 6-methylaminopurine . The chemical specificity of the second peak (B) methylase could not be established due to very high lability of the enzyme in this fraction . Specific endonuclease was found in the gradient zones eluted by 0.1--0.2 M and 0.65--0.75 M NaCl . It is assumed that those enzymes providing for DNA hydrolysis up to the formation of high--molecular discrete fragments, are restricting endonucleases of the SK system . The results obtained strongly suggest the existence of several types of methylases and restricting endonucleases in E . coli SK cells. Biochim Biophys Acta, 1977 Mar 25, 486(3), 451 - 61 Quantitative effects of unsaturated fatty acids in microbial mutants . VII . Influence of the acetylenic bond location on the effectiveness of acyl chains; Lands WE et al.; The ability of a series of 18 carbon acetylenic fatty acids to fulfill the unsaturated fatty acid requirements of Escherichia coli and Saccharomyces cerevisiae was investigated . Despite their high melting points (greater than 40 degrees C), several isomers of the acetylenic fatty acids were as efficient or more efficient in supporting growth than the analogous fatty acid having a cis-double bond . The efficiencies of the different positional isomers in supporting cell proliferation varied from essentially 0 cells per fmol for the 2-5 and 13-17 isomers to high values when the acetylenic bond was near the center of the chain: e.g . 45 E . coli and 5.5 S . cerevisiae cells/fmol for the 10 isomer . A striking ineffectiveness of the 9 isomer was observed with E . coli . The 7, 8 and 10 isomers were at least 10-fold more efficient than any of the other positional isomers in supporting the growth of E . coli . In contrast, the 9 isomer was among the most effective acetylenic fatty acids tested with the yeast mutant . Chromatographic analysis of the extracted lipids indicated that each of the acetylenic isomers tested (except delta2 and delta3) could be esterified by the prokaryotic and eukaryotic microorganisms . The content of unsaturated plus cyclopropane acids observed when growth ceased in E . coli cultures supplemented with growth-limiting concentrations of the acetylenic fatty acids ranged from approx . 15 mol% for the 8 isomer to approx . 35 mol% for the 14 and 17 isomers . The 8-11 isomers were observed to be esterified predominantly at the two position in phosphatidylethanolamine of E . coli and in phosphatidylcholine of S . cerevisiae. J Biol Chem, 1977 Mar 25, 252(6), 1873 - 80 DNA polymerases from bakers' yeast; Chang LM; Two DNA polymerases are present in extracts of commercial bakers' yeast and wild type Saccharomyces cerevisiae grown aerobically to late log phase . Yeast DNA polymerase I and yeast DNA polymerase II can be separated by DEAE-cellulose, hydroxylapatite, and denatured DNA-cellulose chromatography from the postmitochondrial supernatants of yeast lysates . The yeast polymerases are both of high molecular weight (greater than 100,000) but are clearly separate species by the lack of immunological cross-reactivity . Analysis of associated enzyme activities and other reaction properties of yeast DNA polymerases provides additional evidence for distinguishing the two species . Enzyme I has no associated nuclease activity but does carry out pyrophosphate exchange and pyrophosphorolysis reactions, and has an associated 3'-exonuclease activity . Enzyme I does not degrade deoxynucleoside triphosphates and cannot utilize a mismatched template . Enzyme II does carry out a template-dependent deoxynucleoside triphosphate degradation reaction and can excise mismatched 3'-nucleotides from suitable template systems . Earlier studies have shown that both Enzyme I and Enzyme II are inhibited by N-ethylmaleimide . The yeast enzymes are not identical to any known eukaryotic or prokaryotic DNA polymerases . In general, Enzyme I appears to be most similar to eukaryotic DNA polymerase alpha and Ezyme II exhibits properties of prokaryotic DNA polymerases II and III. Philos Trans R Soc Lond B Biol Sci, 1977 Mar 21, 277(955), 201 - 26 The time and duration of meiosis; Bennett MD; Ever since meiosis was recognized as a process there has been a continuing interest in its temporal aspects . Two main types of meiotic timing experiments have been conducted: first, experiments to estimate the duration of meiosis (and sometimes its stages); second, experiments to locate the sensitive stage(s) when exposure of meiocytes to various treatments can affect meiotic chromosome behaviour (e.g . pairing or recombination) . Such experiments have played an important role in increasing our understanding of the meiotic process . The duration of meiosis has been estimated in about 70 organisms, including two prokaryotes (yeast and Chlamydomonas) and the following eukaryotes: 1 Basidiomycete (Coprinus lagopus), 2 Gymnosperms (Larix decidua and Thuja plicata gracilis) . at least 39 angiosperms, and at least 26 animal species . The duration of female meiosis has been estimated in far fewer species than male meiosis . However, estimates of the duration of female meiosis are available for 6 angiosperms . Drosophila melanogaster, Xenopus laevis, and several mammals . Comparison of these data shows that the duration of meiosis is one of the most variable aspects of the meiotic process, ranging from less than 6 h in yeast to more than 40 years in the human female . Developmental holds at different stages of meiosis are common in plants and animals, and inevitably prolong the meiotic division . However, even among species without developmental holds, the duration of meiosis is very variable . For instance, in animals it ranges from about 1-2 days in male Drosophila melanogaster to more than 24 days in male Homo sapiens and several Orthopterans . Despite the large variation in the duration of meiosis three generalizations can be made: (i) first prophase is always very long compared with the remaining meiotic stages, (ii) the rate of meiotic development is very slow compared with the rate of development in dividing somatic meristem cells of the same organisms under the same conditions, (iii) the duration of meiosis is characteristic of the genotype and species . Four main factors have been recognized which effect or determine the duration of meiosis, namely (1) environmental factors (e.g . temperature); (2) nuclear DNA content; (3) ploidy level of the organism; and, (4) the genotype . Because nuclear DNA content plays a major role in determining the duration of meiosis, it has been suggested that DNA influences the rate of meiotic development in two ways: first through its informational content (the genotype), and second indirectly by the physical and mechanical effects of its mass independently of its informational content (i.e . the nucleotype) . Thus, the observed duration of meiosis is the result of a complex genotype-nucleotype-environment interaction . With the obvious exception of variation caused by developmental holds, changes in the duration of meiosis usually involve proportional changes in the durations of all its stages... Chromosoma, 1977 Mar 7, 60(1), 39 - 47 The structure of mesokaryote chromosome; Hamkalo BA et al.; Condensed and dispersed forms of the chromosomes of the dinoflagellate, Prorocentrum micans, deposited on grids by the microcentrifugation technique were studied by electron microscopy . In the normally condensed form, the chromosomes appear as banded rods surrounded by a peripheral cloud of partially dispersed fibers . Single fibers in these and in extensively dispersed preparations appear as smooth threads of uniform diameter (55-65 A) . The chromosome fibers are contrasted by positive-group-specific stains indicating the presence of cationic moieties associated with the DNA . Occasionally Y-shaped chromosomes are seen; these may be replicating structures . These observations are in general agreement with studies of dinoflagellate chromosomes by other techniques, and provide support for the suggestion that these organisms possess a genome organization whose structure is typical of neither prokaryotes nor eukaryotes, and hence may be intermediate forms. Nucleic Acids Res, 1977 Mar, 4(3), 663 - 71 Wheat embryo mitochondrial 18S ribosomal RNA: evidence for its prokaryotic nature; Bonen L et al.; We present a catalog of sequences of oligonucleotides produced by T1 ribonuclease digestion of 32P-labeled small-ribosomal-subunit RNA ("18S rRNA) isolated from purified wheat embryo mitochondria . This catalog is compared to catalogs published for prokaryotic and chloroplast 16S rRNAs and to preliminary results for wheat cytosol 18S rRNA . These comparisons indicate that: (1) wheat mitochondrial 18S rRNA is clearly prokaryotic in nature, showing significantly more sequence homology with 16S rRNAs than can be expected to arise by chance (p less than 0.000001); (2) shared oligonucleotide sequences include an especially high proportion of those identified as conserved in the evolution of prokaryotic rRNAs; and (3) wheat embryo mitochondrial and cytosol 18S rRNAs retain no more, and perhaps less, than the minimum sequence homology detectable by this sensitive method . These results argue in favor of an endosymbiotic origin for mitochondria. Eur J Biochem, 1977 Mar 1, 73(2), 607 - 15 {Methionyl-tRNA synthetase from wheat embryo: dissociation into subunits (author's transl)}; Chazal P et al.; Wheat -embryo methionyl-tRNA synthetase is a dimeric protein of beta2 structure . When highly diluted, it loses the capacity to catalyze ATP-{32P}PPi exchange and to aminoacylate tRNAMet: at low enzymatic concentrations the rates of formation of{32P}ATP and {14C}methionyl-tRNAMet are lower than those predicatedby extrapolating the rates determined at higher enzyme concentrations . The difference between observed and expected rates becomes greater with decreasing enzyme concentration . Filtration of purified, dilute enzyme preparations on Sephadex G-200 results in the separation of dimer and monomer fractions . The proportion of monomer present increases with increasing pre-incubation times before the assay and demonstrates an equilibrium between active dimers and being shifted towards the production of monomers . Datapreviously gathered for Escherichia coli prolyl-tRNA synthetase and for bovine-pancreatic tryptophanyl-tRNA synthetase, coupled with the present results, suggests that the dissociation of dimeric synthetases may be a general phenomenon in eukaryotes as well as in prokaryotes . The number of sub-units and the dissociation constant were obtained at equilibrium, according to relations adapted to the case of oligomeric enzymes (KD congruent to 13 nM at 25 degrees C and pH 7.5) . Rate constants were determined by kinetic studies of the attainment of equilibrium . The rate constant k1 for monomolecular dissociation was determined to be 1.85- 10-3 s-1 and k2 for the bimolecular association to be 0.145 - 106 M-1 s-1 . The KD calculated from k1 and k2 was coherent with the experimentally determined value, at equilibrium . The sub-unit interactions, which involve only a small quantity of energy (delta G degree congruent to + 11 kcal mol-1; +45 kJ mol-1) at 25 degrees C, depend on the ionic environment of the medium and the presence of substrates . Alkaline pH favors monomer production, while the presence of methionine, (Mg-ATP)2- and tRNAMet protect the synthetase from dissociation . 2-mercaptoethanol and dithioerythritol prevent only slightly the loss of activity . Bovine serum albumin, however, protects the enzyme from dissociation under dilute conditions. Mech Ageing Dev, 1977 Mar-Apr, 6(2), 143 - 52 Systems analysis of possible mechanisms of mammalian aging; Denckla WD; A comparison is made between how bacteria and men use their DNA to accomplish any major biological function . To make this comparison, a modified cybernetic analysis was used . This new type of cybernetic analysis makes a distinction between controlled and regulated systems and may permit an extension of cybernetics into new areas of biology . Prokaryotes have only regulated systems for all major functions, whereas eukaryotes can have both regulated and controlled systems . Several lines of reasoning, including the new cybernetic analysis, suggest that death, as opposed to aging, may be a regulated function in mammals . By analogy with other major regulated developmental functions in mammals, it is also suggested that the hypothalamic-pituitary axis may be the site for the regulation of the time of death . An example of how the pituitary might act on the DNA of peripheral cells to cause possible, severe loss of functional capacity is given by some recent experiments with RNA polymerase activity of liver nuclei from rats of different ages and with different endocrine states. Mol Cell Endocrinol, 1977 Mar, 7(1), 89 - 100 Binding characteristics of L-triiodothyronine to isolated rat liver chromatin; Yoshizato K et al.; The binding characteristics of {125I}-labeled L-triiodothyronine (T3) to chromatin isolated from rat liver nuclei were investigated . Binding of T3 to chromatin showed temperature-, incubation time-, and DNA concentration-dependence . According to Scatchard analysis, the apparent equilibrium dissociation constant was 225 pM, with a maximum binding capacity of about 0.2 pmoles per mg DNA . Displacement studies with unlabeled thyroxine (T4) and T3 showed that the binding sites for T4 might be the same as T3 but the binding affinity of the former was less than that of the latter . The binding was completely inhibited by the eukaryotic RNA polymerase inhibitor, rifampicin AF/021, but not by the prokaryotic inhibitor, rifampicin and alpha-amanitin . These observations indicate that the receptors for T3 have certain properties in common with RNA polymerase or other enzyme proteins which are sensitive to the rifampicin derivative . The hormone--chromatin fragments complex was solubilized from residual chromatin by digestion with DNase, but not with RNase, suggesting that the T3 receptors localize in the DNase-sensitive regions of DNA in the chromatin . This provides a useful method to use to investigate the localization of the receptor proteins in the chromatin and the interaction of the hormone-receptor complex with DNA. Biochemistry, 1977 Feb 22, 16(4), 766 - 76 Initial position of aminoacylation of individual Escherichia coli, yeast, and calf liver transfer RNAs; Chinault AC et al.; Transfer RNAs from Escherichia coli, yeast (Sacharomyces cerevisiae), and calf liver were subjected to controlled hydrolysis with venom exonuclease to remove 3'-terminal nucleotides, and then reconstructed successively with cytosine triphosphate (CTP) and 2'- or 3'-deoxyadenosine 5'-triphosphate in the presence of yeast CTP(ATP):tRNA nucleotidyltransferase . The modified tRNAs were purified by chromatography on DBAE-cellulose or acetylated DBAE-cellulose and then utilized in tRNA aminoacylation experiments in the presence of the homologous aminoacyl-tRNA synthetase activities . The E . coli, yeast, and calf liver aminoacyl-tRNA synthetases specific for alanine, glycine, histidine, lysine, serine, and threonine, as well as the E . coli and yeast prolyl-tRNA synthetases and the yeast glutaminyl-tRNA synthetase utilized only those homologous modified tRNAs terminating in 2'-deoxyadenosine (i.e., having an available 3'-OH group) . This is interpreted as evidence that these aminoacyl-tRNA synthetases normally aminoacylate their unmodified cognate tRNAs on the 3'-OH group . The aminoacyl-tRNA synthetases from all three sources specific argining, isoleucine, leucine, phenylalanine, and valine, as well as the E . coli and yeast enzymes specific for methionine and the E . coli glutamyl-tRNA synthetase, used as substrates exclusively those tRNAs terminating in 3'-deoxyadenosine . Certain aminoacyl-tRNA synthetases, including the E . coli, yeast, and calf liver asparagine and tyrosine activating enzymes, the E . coli and yeast cysteinyl-tRNA synthetases, and the aspartyl-tRNA synthetase from yeast, utilized both isomeric tRNAs as substrates, although generally not at the same rate . While the calf liver aspartyl- and cysteinyl-tRNA synthetases utilized only the corresponding modified tRNA species terminating in 2'-deoxyadenosine, the use of a more concentrated enzyme preparation might well result in aminoacylation of the isomeric species . The one tRNA for which positional specificity does seem to have changed during evolution is tryptophan, whose E . coli aminoacyl-tRNA synthetase utilized predominantly the cognate tRNA terminating in 3'-deoxyadenosine, while the corresponding yeast and calf liver enzymes were found to utilize predominantly the isomeric tRNAs terminating in 2'-deoxyadenosine . The data presented indicate that while there is considerable diversity in the initial position of aminoacylation of individual tRNA isoacceptors derived from a single source, positional specificity has generally been conserved during the evolution from a prokaryotic to mammalian organism. Mol Cell Biochem, 1977 Feb 4, 14(1-3), 143 - 9 Gene expression in mitochondria and bacteria; Herrlich P et al.; Mitochondria and bacteria possess protein synthesizing machineries which are similar in many respects; The regulation of gene expression in mitochondria is unknown . We, therefore, tried to use a well-established prokaryotic regulatory system for the exploration of mitochondrial gene regulation . DNA of the bacte